High impact molding machine

ABSTRACT

An improved impact sand molding machine includes an impacting head supporting a plurality of impacting shoes for impacting sand in a mold for the purpose of obtaining improved packing of the sand around a pattern in the mold. Each impacting shoe is independently mounted on the head and is provided with impact absorbing means to allow each shoe to impact independently of other shoes thereby to compensate for areas of greater and lesser impact resistance on the surface of the mold. The impact machine may be movably mounted for more uniform packing of sand in a mold and for impacting molds of different sizes.

0 United States Patent 1 3,692,093 Taccone 1 Sept. 19, 1972 [54] HIGH IMPACT MOLDING MACHINE 3,528,480 9/1970 Smith. ..164/207 X Inventor: w T E i P Gl'Ona 16511 Primary Examiner-J. Spencer Overholser Assistant Examiner-John S. Brown P t 0 t I [73] Asslgnee g1';g,, g pm Attorney-Patrick J. Walsh [22] Filed: Sept. 8, 1970 57 ABSTRACT PP N04 69,999 An improved impact sand molding machine includes an impacting head supporting a plurality of impacting 52 U.S. Cl ..164/212 shoes for impacting sand in a mold for the p p of [51] Int. Cl ..B22c 15/34 Obtaining improved packing of the sand around a pat- [58] Field of Search ..164/170, 171, 172, 173, 207, tern in the mold. Each impacting shoe is indepen- 164/212; 60/52 HF; 91/41] A; 92/152 dently mounted on the head and is provided with impact absorbing means to allow each shoe to impact in- [56] References Cited dependently of other shoes thereby to compensate for areas of greater and lesser impact resistance on the UNITED STATES PATENTS surface of the mold. The impact machine may be 3,266,103 8/1966 lvarsson ..164/ 173 movably mounted for more uniform packing of sand 3,347,307 10/1967 Hatch ..164/173 in a mold and for impacting molds of different sizes. 3,381,740 5/1968 Janke ..164/173 3,233,291 2/1966 Miller ..164/ 173 4 Claims, 5 ng igures 3,181,208 5/1965 Brauer ..164/173 Q W ///77l SHEEI 1 BF 2 PATENTEDsEP 19 m2 INVENTOR.

PATENTEDSEP 19 1912 SHEEI 2 BF 2 M Ne Zara/v5 INVENTOR.

1 HIGH IMPACT MOLDING MACHINE BACKGROUND OF THE INVENTION tered in local areas of the sand moldsurface. The impact resistance will vary according to the depth of sand beneath the surface of the mold. If a shallow depth of sand covers the pattern plate, the mold surface above the pattern plate will tend to be an area of greater impact resistance whereas an area of the mold surface over a greater depth of sand will tend to have a lesser impact resistance and a greater impact shoe penetration occurs at the sand surface. Further, an impact resistance variation occurs according to the depth of sand over portions of the pattern plate beneath the surface of the molding sand.

. For proper packing of the sand in the mold around the pattern plate it is necessary for the impact shoes to provide uniform impacting force over the entire mold surface. The impact shoes should compensate for variations in impact resistance while applying uniform or nearly uniform impacting force to the sand surface.

SUMMARY OF THE INVENTION In carrying out the invention, an open-ended flask is positioned over a pattern plate to form an upwardly open mold chamber into which sand is introduced by conventional means. The present invention provides for an improved impact molding machine in which impacting shoes are used for packing sand around the pattern plate within the sand mold. Uniform or nearly uniform impacting forces are applied throughout the surface area of the sand mold by each impacting shoe. Each impacting shoe is yieldably mounted on the impact machine so that upon impact the impacting shoe will pound the surface of the mold and deflect in relation to the impact resistance encountered by the shoe. If the impacting shoe contacts a portion of the sand mold area under which there is no pattern then the shoe will encounter relatively little impact resistance and accordingly the shoe will be deflected, a small amount, if at all. On the other hand if the shoe encounters an area of the mold above the pattern then relatively high impact resistance can be expected and the shoe will deflect a relatively larger amount on encountering such resistance.

The deflected shoes are independently mounted upon the impact machine and preferably include an impact cushioning means which may be a fluid displacement means or which may be spring means for absorbing the impact force as the shoe deflects under impact.

In order to provide further uniformity of sand packing it is within the purview of the present invention to provide carriage means for moving the impacting machine over the surface of the sand mold to more uniformly impact the sand on the surface of the mold. It is within the scope of the present invention to provide for a movable impacting head which may be used for different size molds without having to change the shoe pattern.

In one form of the present invention the carriage means is a longitudinal trackway having rails for receiving a moving bridge longitudinally of a molding chamber. The impact machine rides transversely directed tracks on the bridge for movement transversely of the molding chamber. By this arrangement the im pact machine can impact the entire surface of the sand mold.

In another form the impact machine may be positioned on a fixed bridge over sand molds which move longitudinally through the bridge. The longitudinal movement of the sand molds may be intermittent to allow the impact shoes to impact the entire mold surface.

DESCRIPTION OF THE DRAWINGS A preferred embodiment of the present invention has been chosen for illustrating the principles of the invention and is shown in the accompanying drawing wherein:

FIG. 1 is a side elevation view partly in section illustrating a form of impact molding machine in position with respect to a sand molding chamber;

FIG. 2 is a fragmentary view in section illustrating the independent mounting of an impact shoe with respect to the impact molding machine;

FIG. 3 is a side elevational view illustrating a modified form of the improved molding machine according to the present invention;

FIG. 4 is a fragmentary view illustrating a modified form impacting shoe mounting;

FIG. 5 is a front elevational view illustrating a carriage and trackway means for mounting the improved impact molding machine with respect to a molding chamber.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1 the impact molding machine 1 includes a trackway 2 and car 4 for moving a molding chamber 6 into position for the impacting operation. The molding chamber 6 includes a flask 8 and a pattern plate 10 and sand 12 filling the flask covering the pattern plate. The pattern plate 10 may be nonuniform in cross section and presents a portion 10a of its surface in closer relationship to the surfaceof sand while another area 1% of the pattern plate is further removed from the surface of the sand. The portions of the sand mold where the pattern plate is closest to the surface of the sand will present areas of relatively high resistance to impact. In areas where there is a greater depth of sand there will be lesser resistance to impact.

In its general arrangement, the impact molding machine includes a frame 14 mounting animpacthead 16 in position over the molding chamber. The impact head includes a carrier block 18 for carrying and moving a plurality of impact shoes 20 toward and away from the molding chamber.

The impact head 16 includes a double power unit 17 for moving the impact shoes 20 toward and back from the molding chamber. The double power unit is arranged to provide for quick impact of the shoes against the sand surface followed by a continued squeezing of the shoes into the sand surface. Applicant has found that the desired quick impact and squeeze after impact are best obtained by the use of an air power unit 19 acting in concert with an hydraulic power unit 21.

The preferred double power unit includes a lower cylinder 22 mounted at its lower end wall 23 to the machine frame. The cylinder includes a piston 24 and piston rod 26 to which the carrier block (and impact shoes) are connected by suitable means such as bolts 28. Suitable piping 36, 37 provides for inlet of compressed air to the cylinder for impacting and recocking the impact shoes.

The inlet line 36 admits air under sufficient pressure for impacting the shoes against the sand surface. The lower inlet line 37 admits air under pressure for recocking the cylinder (and impact shoes) for a repeat cycle. A valve mechanism (not shown) disclosed in said application, Ser. No. 799,423 is suitable for admitting air at a pressure between 40 to 60 psi to the air cylinder. A vent is included in the valve mechanism for exhausting air from the cylinder through lines 36 and 37 as appropriate for operation of the cylinder.

The double power unit further includes an upper cylinder 30 mounted at its lower end 31 wall to the lower cylinder. Preferably the upper cylinder is hydraulically operated. if desired, the upper and lower cylinders may be arranged as illustrated in FIG. 1 to share the cylinder end wall 31. The upper cylinder includes a piston 32 and rod 34 which passes through the cylinder end wall 31 for connection to the lower cylinder rod 26. Suitable piping 38 provides for inlet of hydraulic fluid to the cylinder to obtain desired power movement for continued squeezing of the shoes against the sand after impact. The lower line 39 provides for venting the underside of piston 32. f The double power unit further includes a surge tank 42 for receiving and returning hydraulic fluid to the upper cylinder during the recocking and impacting/squeezing operations, respectively. During preliminary travel of the impact head, hydraulic fluid flows from the surge tank 42 into the upper cylinder 30. Fluid under pressure enters the upper cylinder through the inlet line 38 to provide for squeeze of the sand by the impact shoes after impact occurs. It is to be understood that faster squeeze action occurs by having fluid in the cylinder when the inlet line 38 is opened.

A valve 44 in the surge tank opens and closes the tank to the upper cylinder. The valve may be actuated by hydraulic cylinder 46 in timed relation to the movement of the upper piston 32 to provide for storage and flow of surge fluid as desired. The valve is open and fluid fills the cylinder 30 as the piston 32 descends for the impact operation. As the unit impacts, the valve 44 closes and hydraulic fluid under pressure of approximately 2,000 psi enters the cylinder through line 38 for the squeeze operation. When the squeeze action is completed, the valve 44 opens to receive fluid from the cylinder 30 as the piston 32 moves upwardly to its initial position in preparation for the next cycle.

The surge tank 42 may be mounted on the upper cylinder head 48 and provided with fluid passages 50 for flow to and from the cylinder.

As shown in FIG. 2, each impact shoe is mounted by suitable fasteners 52 at the lower end of a rod 54 which is received in a complimentary sleeve 56. A cross pin 58 cooperates with a slot 60 to retain the rod 54 in position with respect to the sleeve. The sleeve in turn is mounted by suitable means 62 on the carrier block 18. The carrier block is reinforced by vertical and horizontal structural members 64 and 66.

The interior of the sleeve 56 is provided with a liner 68 which defines a cylinder 70 for receiving a fluid, preferably hydraulic, to act as a cushion or shock absorber for sudden upward movements of the rod into the cylinder during the impact operation.

A hydraulic circuit 72 cooperates with the cylinder 70 to cushion the impact of each shoe upon the sand surface and to reset the shoes after each impact cycle. The hydraulic circuit communicates with the cylinder through a port 74 in the cylinder head 75 and a fluid passage 76 in the carrier block.

The hydraulic circuit includes suitable piping 78, a pressure relief valve 80 set to give a pressure of approximately l00-200 psi on the mold surface, a surge tank 82, and a flow check valve 84. As fluid pressure increases in the cylinder 70, during impact of the shoe on the sand, the pressure relief valve will open permitting fluid to flow into the surge tank. The surge tank is pressurized by compressed air through line 86 (40-60 psi) to provide for return flow of the fluid via the flow check valve 84 to the cylinder. This return flow to the cylinders resets the impact shoes for the next operation.

Preferably, a single hydraulic circuit cooperates with several shoes to define a hydraulic zone for reducing the quantity and complexity of hydraulic circuitry.

if desired, the hydraulic system may be provided with heat exchangers for cooling the hydraulic fluid to dissipate heat of impact.

As shown in FIG. 3, an impact shoe 20 will penetrate to a depth depending on the amount of resistance encountered at the surface of the mold. Because of its independent mounting, each shoe will deflect according to the resistance encountered. The resistance encountered depends upon depth and quantity of sand located under the impact shoe. In this way a uniform, or nearly uniform, force is applied to the sand mold surface by all shoes. The reference numerals of the modification of FIG. 3 correspond to the reference numerals of FIG. 1.

In a modification according to the present invention as shown in FIG. 4 a compression member 92, which preferably is a spring, may be used to absorb the shock or upward impact of each shoe 20', during the sand impacting operation. This spring arrangement eliminates the need for hydraulic systems and is found to have a very substantial life and is able to withstand repeated impact cycles without failure. In this modification, the impact unit includes a sleeve 56' fitted with a liner 68' to receive the compression member 92 is made up of spring discs. The compression member bears against the cylinder head 75' and the piston rod 54 during operation. A cross pin 58' limits piston rod movement in the vertical direction. A suitable collar 83 retains the impact assembly in place on the carrier block 18.

The compression member is a stack of discs 92 of the type known as a Bellville washer each being a portion of the surface of a sphere in form and having a hole in its center. The washers are stacked alternately concave to concave and convex to convex. This compression member absorbs energy when loaded by squeezing the discs and enlarging their outside diameter.

I may move transversely along the top of the carrier on rails 105 so that the entire surface area of the mold may be impacted. If desired a companion fixed width conveyor 106 may be located in close proximity to the variable width conveyor so that one impact machine may service two conveyors. The fixed width conveyor corresponds to the effective width of the molding chamber 6 so that the impact machine may be set in the transverse direction and the impact operation performed by moving the mold longitudinally. If desired the impact molding machine may cross a bridge member 108 to reach the fixed width conveyor.

In operation, a molding chamber 6 (FIG. 1) including a flask 8, a pattern plate 10 and sand 12 covering the pattern plate is brought into position under the shoes of the impact molding machine 1. By operat ing a pneumatic power unit 19 the impact cylinder 22 causes the shoes 20 to impact against the surface of the sand thereby to pack sand in the mold around the pattern plate. In order to achieve optimum packing of sand, a hydraulic power unit 21 applies a squeezing action to the impact shoes after initial impact has occurred. A surge tank 42 provides for rapid filling of the cylinder so that the impact and squeeze operations occur without interim delay.

Because of differences in the shapes of pattern plates used in different molding operations the impact shoes will encounter greater or lesser impact resistance according to the depth and quantity of sand underlying the area of impact of the pattern shoe. To prevent overloading the area of greatest impact resistance each of the shoes is independently mounted with respect to the carrier block of the machine. Each independent mounting includes cushioning means contained in the cylinder 70 which'forms the upper part of the shoe mounting sleeve 56. In one form the cushioning means includes a suitable fluid, preferably hydraulic, which absorbs energy of impact as it 'flows through the hydraulic circuit 72 as shown in FIG. 2. In another form the shock absorbing means may be a spring member 90' located in the cushion cylinder to absorb the energy of impact during the operation of the machine. The independent mounting of the impact shoes provides for uniform or nearly uniform loading of the sand over its entire surface during the impact operation.

To further provide for uniform impacting of the sand over the entire surface of a large mold the impact machine may be mounted on suitable carriages 100 and 98 (FIG. 5) having provisions for moving transversely and longitudinally of the mold surface. If desired, the impacting machine may be fixed. in a transverse position while the mold is moved longitudinally to provide for impact over the entire mold surface.

What is claimed is: t Y

1. A machine for impacting sand in a molding chamber comprising a support frame, a plurality of impacting shoes for impacting the sand, a first pneumatically operated power unit mounted on said frame and adapted to support the shoes in operative relation to a molding chamber, said first power nit having a cylinder, a piston, a piston rod, means or connec mg the support shoes to said piston rod, a second hydraulically operated power unit mounted on said first power unit, said second power unit having a cylinder, piston and piston rod, the piston rod of the second cylinder being connected in axial alignment to the first cylinder piston rod so that the impacting shoes may be impacted on the sand by the first power unit and the shoes may be squeezed against the sand by the second power unit, a surge tank for delivering fluid to the second power unit during the impact stroke of the piston and for receiving fluid during the return stroke of the piston, and valve means operating in timed relation to piston movement for opening and closing the surge tank.

2. The machine set forth in claim 1 in which the means for connecting the impacting shoes to the piston rod of the first power unit includes cushioning means for absorbing the force of impact whereby the impacting shoes may penetrate the surface of the sand mold independently of other impacting shoes.

3. The machine set forth in claim 2 in which the cushioning means comprises a cylinder for each impacting shoe, hydraulic fluid in the cylinder, a piston in each cylinder cooperating with an impacting shoe and transmitting impact forces from said shoe to said fluid, a hydraulic circuit for receiving and dissipating the energy of the fluid as it moves through the circuit, the hydraulic circuit including piping for receiving fluid from and returning fluid to each cylinder, a pressure relief valve, a pressurized surge tank, and a flow check valve, wherein fluid passes through the pressure relief valve and enters the surge tank, and is returned from the surge tank under pressure through the check valve to each cylinder.

4. The machine set forth in claim 2 in which the cushioning means comprises a cylinder for each impacting shoe, a spring member located in each cylinder, and a piston and piston rod cooperating with the spring member and its associated impacting shoe for transmitting impact forces from said shoe to said spring member. 

1. A machine for impacting sand in a molding chamber comprising a support frame, a plurality of impacting shoes for impacting the sand, a first pneumatically operated power unit mounted on said frame and adapted to support the shoes in operative relation to a molding chamber, said first power unit having a cylinder, a piston, a piston rod, means for connecting the support shoes to said piston rod, a second hydraulically operated power unit mounted on said first power unit, said second power unit having a cylinder, piston and piston rod, the piston rod of the second cylinder being connected in axial alignment to the first cylinder piston rod so that the impacting shoes may be impacted on the sand by the first power unit and the shoes may be squeezed against the sand by the second power unit, a surge tank for delivering fluid to the second power unit during the impact stroke of the piston and for receiving fluid during the return stroke of the piston, and valve means operating in timed relation to piston movement for opening and closing the surge tank.
 2. The machine set forth in claim 1 in which the means for connecting the impacting shoes to the piston rod of the first power unit includes cushioning means for absorbing the force of impact whereby the impacting shoes may penetrate the surface of the sand mold independently of other impacting shoes.
 3. The machine set forth in claim 2 in which the cushioning means comprises a cylinder for each impacting shoe, hydraulic fluid in the cylinder, a piston in each cylinder cooperating with an impacting shoe and transmitting impact forces from said shoe to said fluid, a hydraulic circuit for receiving and dissipating the energy of the fluid as it moves through the circuit, the hydraulic circuit including piping for receiving fluid from and returning fluid to each cylinder, a pressure relief valve, a pressurized surge tank, and a flow check valve, wherein fluid passes through the pressure relief valve and enters the surge tank, and is returned from the surge tank under pressure through the check valve to each cylinder.
 4. The machine set forth in claim 2 in which the cushioning means comprises a cylinder for each impacting shoe, a spring member located in each cylinder, and a piston and piston rod cooperating with the spring member and its associated impacting shoe for transmitting impact forces from said shoe to said spring member. 